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The Supplement to the Tropical Agriculturist 



by changkolling must be governed by com- 

 mon sense. Fomes is found first on a log, 

 generally, and is transferred to the tree when 

 the roots reach it, once there it grows and 

 eventually the tree dies. It is then necessary 

 to isolate the attacked tree, from fellow trees 

 and from prostrate logs— not to save the tree 

 attacked but to save the others. There was 

 much to be learned about the origin and nature 

 of the pest, but there was no doubt that it 

 attacked the Para rubber tree. The earth 6 in. 

 deep is opened up : if the tree is attacked 

 by fungus, the roots are black; if healthy, white 

 and yielding latex. In guarding against the 

 spread therefore, the area affected must be de- 

 termined, and then every bit of timber on it 

 burned off. The area is changkolled to eighteen 

 inches, all the timber taken out, and put aside 

 for burning and every bit must be taken out 

 and burned. It is very difficult to kill a fungus 

 and spraying or applications generally could 

 only prevent spreading. Above all things it was 

 absoulutely necessary to be thorough. 



Another fungus attacks the stems and branches 

 of rubber trees, showing long streaks of latex 

 down it. It runs on a branch, or the main stem 

 and is rather easily identified, even without a 

 microscope. This black fungus can be cut out of 

 stems, or branches cut off and burned — it seems 

 easily checked. In cutting branches or a stem, 

 the saw should be used after hacking down, 

 and a good slope cut ; after which tar should 

 be applied, to prevent other fungus entering. 

 Branches should be cut off close to the stem, 

 when a clean heal results. There is a limit to 

 the amount of tarring a tree will stand, it may 

 survive a narrow strip but not very much. 

 White- washing will keep away deer and rats and 

 will not injure the trees. All remedies have to 

 be applied with knowledge, and his Department 

 were quite willing to supply information and 

 give assistance in any way they could. 



Discussion. 



In answer to questions, Mr. Gallagher said 

 that " die-back " might be due to several causes. 

 When the fungus he had spoken of attacked 

 trees, this appearance followed. The treatment 

 was to cut off the affected part, three feet below 

 the lowest point to which the disease had 

 reached, ami burnt it. It might result from 

 interference with the water supply. Peaty soils 

 were sometimes too acid and careful planters on 

 observing any sign of it tested the water with 

 litmus, and if it proved acid, applied lime. He 

 did not know that fomes was ever more than 

 two feet deep, though he knew of no reason 

 why it should not go deeper. It was ex- 

 ceedingly necessary to be on the look-out for 

 it and to isolate and burn affected plants. In 

 other than peaty soils, charcoaling could be 

 tried. Pink fungus was the stem and branch 

 fungus he had mentioned. He believed it existed 

 in kampongs, and on Java trees. It had not 

 been reported from the Peninsula. Fomes 

 might spread by spores, but he had no informa- 

 tion as to that. The colours were very fugitive, 

 and he could not show them any specimens, 

 but if they suspected it, the sample might be 

 sent to the Department, properly labelled, and 

 they would then report on it. — S. F. Press, Feb. 7. 



THE "STRENGTH" OF OLD AND 

 YOUNG RUBBER. 



We have seen it asserted in Ceylon that 

 the theory — the older the rubber, the greatly 

 superior it is in strength — rests merely on the 

 rough and ready practical tests of buyers and 

 manufacturers. Mr. Henry P. Stevens, M.A., 

 f.i.c. in his article in the Quarter-Century num- 

 ber of the India Rubber Journal points out the 

 following— among factors other than superior 

 strength (which he does not admit to be inevi- 

 table) which tend to assist Fine Para in public 

 popularity as against Plantation : — 



(a) Fine hard is the specified quality in a 

 number of War Office, Admiralty, and other 

 contracts, and must therefore be used for many 

 goods quite apart from the question of merit. 



(6) Fine hard is to be had in very large 

 quantities in fairly uniform quality, so that it 

 can be depended on to produce uniform results, 

 while plantation rubber is put on the market 

 in almost every imaginable variety of shape, 

 form and quality. Even when an estate is ship- 

 ping a product of uniform quality, the quantity 

 in most cases is relatively small. If a manu- 

 facturer could depend on getting the greater 

 part of every consignment of the same rubber 

 from a given plantation, the amount would not 

 be more than he would require to keep him 

 going on one or two special lines. 



(c) Plantation rubber has not yet stood the 

 test of time. 



It is stated that local experience and scientific 

 opinion is opposed to the view that old and young 

 trees give rubber of equal strength. But here 

 again we have a valuable opinion on the other 

 side, from the other article by the prominent 

 home chemist above quoted, who has consider- 

 able experience of rubber testing as follows: — 



The quality of plantation rubber is, of course, 

 largely dependent on the method employed in 

 its preparation. I may here call attention to 

 a recent paper read before the Society of Che- 

 mical Industry by Mr. Beadle and myself on 

 3rd May last. The results of tests detailed in 

 that paper on rubber vulcanised with heat in 

 the usual manner showed that the samples of 

 Ceylon plantation rubber examined were slightly 

 — yet distinctly — inferior in physical qualities to 

 the sample of hard cure Para. Another series of 

 tests on manufacturers' samples of cold cured 

 goods made from hard cure and the best plan- 

 tation, were in favour of the plantation samples. 

 Another important point was brought out in 

 this work, namely that a difference in the age 

 of the trees, say from five to twenty years old 

 appeared to have little or no effect on the phy- 

 sical qualities of the vulcanised rubbers. 



I was glad to notice that Mr. Parkin in this 

 Journal (2nd November, 1908) had come to the 

 same conclusion on purely botanical grounds, 

 and wrote that he should be rather surprised 

 to find any marked difference in the quality 

 of the rubber drawn from ten-year-old trees, 

 as compared with twenty-year-old ones as in 

 both cases the latex is formed from secondary 

 growth and is not comparable with that 

 derived from laticiferous vessels of primary 

 growth in the twigs and leaves. 



